Mechanism of Oxidation of Ethane to Ethanol at lron(IV)-Oxo Sites in Magnesium-Diluted Fe(dobdc).
The catalytic properties of the metal-organic framework Fe(dobdc), containing open Fe(ll) sites, include hydroxylation of phenol by pure Fe(dobdc) and hydroxylation of ethane by its magnesium-diluted analogue, FeMg(dobdc). In earlier work, the latter reaction was proposed to occur through a redox me...
| Publicado en: | Journal of the American Chemical Society Vol. 137; no. 17; pp. 5770 - 5782 |
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| Autores principales: | , , , , , , , |
| Formato: | Artículo |
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American Chemical Society
5/6/2015
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=102837734&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 102837734 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 5/6/2015 vid: 137 iid: 17 pid: 997 pub: American Chemical Society artinfo: ui: 102837734 10.1021/jacs.5b00382 ppf: 5770 ppct: 12 formats: tig: atl: Mechanism of Oxidation of Ethane to Ethanol at lron(IV)-Oxo Sites in Magnesium-Diluted Fe(dobdc). aug: au: Verma, Pragya Vogiatzis, Konstantinos D. Planas, Nora Borycz, Joshua Xiao, Dianne J. Long, Jeffrey R. Gagliardi, Laura Truhlar, Donald G. affil: Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, Minnesota 55455, United States Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States Department of Chemistry, University of California, Berkeley, California 94720, United States Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720, United States su: Catalysis synthesis Carbon-hydrogen bonds Ethanes Density functionals Ethanol Chemical symbiosis sug: subj: Catalysis synthesis Carbon-hydrogen bonds Ethanes Density functionals Ethanol Chemical symbiosis ab: The catalytic properties of the metal-organic framework Fe(dobdc), containing open Fe(ll) sites, include hydroxylation of phenol by pure Fe(dobdc) and hydroxylation of ethane by its magnesium-diluted analogue, FeMg(dobdc). In earlier work, the latter reaction was proposed to occur through a redox mechanism involving the generation of an iron(lV)-oxo species, which is an intermediate that is also observed or postulated (depending on the case) in some heme and nonheme enzymes and their model complexes. In the present work, we present a detailed mechanism by which the catalytic material, FeMg(dobdc), activates the strong C-H bonds of ethane. Kohn-Sham density functional and multireference wave function calculations have been performed to characterize the electronic structure of key species. We show that the catalytic nonheme-Fe hydroxylation of the strong C-H bond of ethane proceeds by a quintet single-state rt-attack pathway after the formation of highly reactive iron-oxo intermediate. The mechanistic pathway involves three key transition states, with the highest activation barrier for the transfer of oxygen from N20 to the Fe(II) center. The uncatalyzed reaction, where nitrous oxide directly oxidizes ethane to ethanol is found to have an activation barrier of 280 kj/mol, in contrast to 82 kj/mol for the slowest step in the iron(IV)-oxo catalytic mechanism. The energetics of the C-H bond activation steps of ethane and methane are also compared. Dehydrogenation and dissociation pathways that can compete with the formation of ethanol were shown to involve higher barriers than the hydroxylation pathway. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2015 holdings: @attributes: islocal: N |
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